1. Field
One embodiment of the invention relates to a power saving control technique preferably applied to an information processing apparatus, such as a battery-powered portable type personal computer.
2. Description of the Related Art
In recent years, battery-powered and readily portable information processing apparatuses, such as notebook type personal computers or PDAs (Personal digital assistants) have come into wide use. Further, the wireless communication environment is well-serviced as a social infrastructure. Users with this kind of information processing apparatus can thereby work outdoors or on the move and keep up to date with the most recent data, and exchange data.
In this kind of information processing apparatus, various proposals to realize power saving have been made so far in order to secure continuous battery-powered time for as long as possible (e.g., see Jpa. Pat. Appln. KOKAI Publication No. 11-73256). The foregoing Publication No. 11-73256 discloses the information processing apparatus including the following technique. According to the technique, when all peripheral devices (having a sound signal output function) connected to a sound controller enter a mute state, the sound controller is transferred to a power saving mode. In this way, the information processing apparatus realizes power saving.
This kind of information processing apparatus has a possibility of being used in various situations, that is, during movement and outdoors. Of users having this kind of information processing apparatus, some users set the information processing apparatus to sound output volume zero, a so-called volume full-mute state in view of consideration of the environment. In this case, even if a peripheral device returns from a mute state, and a sound controller reproduces a sound signal output from such peripheral device, the reproduced sound is not output. Namely, in such a case, preferably, the sound controller is also maintained in a power saving mode in view of power saving.
The foregoing circumstances are not limited to the sound output from a peripheral device. For example, the same circumstances as the sound output from the peripheral devices are present in an operating sound and warning sound output from an operating system in response to a user's operation. Therefore, it is desired to provide some measures to achieve power saving.